Karasu-gane

Japanese: 烏金 - からすがね

〘 noun 〙 A type of usury in the Edo period. Money was lent for a day and a night. Theater teahouses, restaurants, and the like borrowed money to cover their needs for that night. Crow. ※Essay, Tosei Takeno Zokudan (1757) - Kuruma Baba: "For one ryo, the interest is 200 mon per day, and the rule is that you don't borrow again until tomorrow. Is there really any money with such outrageous interest? <omitted> This money is called crow money."

U-kin [Crow gold]

〘Noun〙① Another name for iron. [Honsho Komoku - Metal and Stone Section - Iron - Explanation]② A black metal used in engraving. Shakudo (copper) . [Modern Technical Dictionary (1931)]③ Another name for ink. [Shinsen Ruiju Orai (around 1492-1521)]

Source: The Selected Edition of the Japanese Language Dictionary About the Selected Edition of the Japanese Language Dictionary Information

Japanese:

〘名〙江戸時代の高利貸の一種。一昼夜を限り貸し付けたもの。芝居茶屋や飲食店などが、その夜限りの入用をまかなうために借り入れた。からす。※随筆・当世武野俗談（1757）車婆々「一両かしては一日の利足二百文づつ、明日迄はまたざるを掟とす。此けしからぬ高利の金も有ものかな。〈略〉此金を烏金といふ」